CGEM BOSS 6.6.5.i
BESIII Offline Software System
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Public Member Functions | List of all members
EvtResonance Class Reference

#include <EvtResonance.hh>

Public Member Functions

EvtResonance & operator= (const EvtResonance &)
 
 EvtResonance (const EvtVector4R &p4_p, const EvtVector4R &p4_d1, const EvtVector4R &p4_d2, double ampl=0.0, double theta=0.0, double gamma=0.0, double bwm=0.0, int spin=0)
 
virtual ~EvtResonance ()
 
const EvtVector4R & p4_p ()
 
const EvtVector4R & p4_d1 ()
 
const EvtVector4R & p4_d2 ()
 
double amplitude ()
 
double theta ()
 
double gamma ()
 
double bwm ()
 
int spin ()
 
EvtComplex resAmpl ()
 
EvtComplex relBrWig (int i)
 

Detailed Description

Definition at line 31 of file EvtResonance.hh.

Constructor & Destructor Documentation

◆ EvtResonance()

EvtResonance::EvtResonance ( const EvtVector4R & p4_p,
const EvtVector4R & p4_d1,
const EvtVector4R & p4_d2,
double ampl = 0.0,
double theta = 0.0,
double gamma = 0.0,
double bwm = 0.0,
int spin = 0 )

Definition at line 51 of file EvtResonance.cc.

53 :
54 _p4_p(p4_p),_p4_d1(p4_d1), _p4_d2(p4_d2),_ampl(ampl), _theta(theta),
55 _gamma(gamma), _bwm(bwm), _spin(spin) {}
EvtResonance::p4_d2
const EvtVector4R & p4_d2()
Definition EvtResonance.hh:50
EvtResonance::p4_d1
const EvtVector4R & p4_d1()
Definition EvtResonance.hh:49
EvtResonance::gamma
double gamma()
Definition EvtResonance.hh:60
EvtResonance::p4_p
const EvtVector4R & p4_p()
Definition EvtResonance.hh:48
EvtResonance::theta
double theta()
Definition EvtResonance.hh:57

◆ ~EvtResonance()

EvtResonance::~EvtResonance ( )
virtual

Definition at line 31 of file EvtResonance.cc.

31{}

Member Function Documentation

◆ amplitude()

double EvtResonance::amplitude ( )
inline

Definition at line 54 of file EvtResonance.hh.

54{ return _ampl; }

◆ bwm()

double EvtResonance::bwm ( )
inline

Definition at line 63 of file EvtResonance.hh.

63{ return _bwm; }

◆ gamma()

double EvtResonance::gamma ( )
inline

Definition at line 60 of file EvtResonance.hh.

60{ return _gamma; }

◆ operator=()

EvtResonance & EvtResonance::operator= ( const EvtResonance & n)

Definition at line 35 of file EvtResonance.cc.

36{
37 if ( &n == this ) return *this;
38 _p4_p = n._p4_p;
39 _p4_d1 = n._p4_d1;
40 _p4_d2 = n._p4_d2;
41 _ampl = n._ampl;
42 _theta = n._theta;
43 _gamma = n._gamma;
44 _spin = n._spin;
45 _bwm = n._bwm;
46 return *this;
47}
n
const Int_t n
Definition DataBase/tau_mode.c:65

◆ p4_d1()

const EvtVector4R & EvtResonance::p4_d1 ( )
inline

Definition at line 49 of file EvtResonance.hh.

49{ return _p4_d1; }

◆ p4_d2()

const EvtVector4R & EvtResonance::p4_d2 ( )
inline

Definition at line 50 of file EvtResonance.hh.

50{ return _p4_d2; }

◆ p4_p()

const EvtVector4R & EvtResonance::p4_p ( )
inline

Definition at line 48 of file EvtResonance.hh.

48{ return _p4_p; }

◆ relBrWig()

EvtComplex EvtResonance::relBrWig ( int i)

Definition at line 114 of file EvtResonance.cc.

114 {
115
116//this function returns relativistic Breit-Wigner amplitude
117//for a given resonance (for P-wave decays of scalars only at the moment!)
118
119 EvtComplex BW;
120 EvtVector4R _p4_d3 = _p4_p-_p4_d1-_p4_d2;
121 EvtVector4R _p4_12 = _p4_d1 + _p4_d2;
122
123 //EvtVector4R _p4_pm3 = _p4_p - _p4_d3;
124 //EvtVector4R _p4_1m2 = _p4_d1 - _p4_d2;
125
126 //double msq12 = _p4_12.mass2();
127 double msq13 = (_p4_d1 + _p4_d3).mass2();
128 double msq23 = (_p4_d2 + _p4_d3).mass2();
129 double msqParent = _p4_p.mass2();
130 double msq1 = _p4_d1.mass2();
131 double msq2 = _p4_d2.mass2();
132 double msq3 = _p4_d3.mass2();
133
134 double M;
135
136 double p2 = sqrt((_p4_12.mass2() - (_p4_d1.mass() + _p4_d2.mass())*(_p4_d1.mass() + _p4_d2.mass()))*(_p4_12.mass2() - (_p4_d1.mass() - _p4_d2.mass())*(_p4_d1.mass() - _p4_d2.mass())))/(2.0*_p4_12.mass());
137
138 double p2R = sqrt((_bwm*_bwm - (_p4_d1.mass() + _p4_d2.mass())*(_p4_d1.mass() + _p4_d2.mass()))*(_bwm*_bwm - (_p4_d1.mass() - _p4_d2.mass())*(_p4_d1.mass() - _p4_d2.mass())))/(2.0*_bwm);
139
140 double gam, R;
141
142if (i == 1) {
143//consider this the K resonance
144
145 R = 2.0/(0.197);
146
147}
148else R = 5.0/(0.197);
149
150 gam = _gamma*(_bwm/_p4_12.mass())*(p2/p2R)*(p2/p2R)*(p2/p2R)*((1 + R*R*p2R*p2R)/(1 + R*R*p2*p2));
151 M = (msq13 - msq23 - (msqParent - msq3)*(msq1 - msq2)/(_bwm*_bwm))*sqrt((1 + R*R*p2R*p2R)/(1 + R*R*p2*p2));
152 //M = (msq13 - msq23 - (msqParent - msq3)*(msq1 - msq2)/(_p4_12.mass2()))*sqrt((1 + R*R*p2R*p2R)/(1 + R*R*p2*p2));
153
154 BW = sqrt(_gamma)*M/((_bwm*_bwm - _p4_12.mass2()) - EvtComplex(0.0,1.0)*gam*_bwm);
155
156 return BW;
157
158}
EvtVector4R::mass
double mass() const
Definition EvtVector4R.cc:39
EvtVector4R::mass2
double mass2() const
Definition EvtVector4R.hh:116
rb::R
complex_t R(double Q2, double M2, double G, double Mp2, double Mm2)
Definition TUtil.h:27

Referenced by EvtDDalitz::decay().

◆ resAmpl()

EvtComplex EvtResonance::resAmpl ( )

Definition at line 59 of file EvtResonance.cc.

59 {
60
61 double pi180inv = 1.0/EvtConst::radToDegrees;
62
63 EvtComplex ampl;
64 //EvtVector4R _p4_d3 = _p4_p-_p4_d1-_p4_d2;
65
66 //get cos of the angle between the daughters from their 4-momenta
67 //and the 4-momentum of the parent
68
69 //in general, EvtDecayAngle(parent, part1+part2, part1) gives the angle
70 //the missing particle (not listed in the arguments) makes
71 //with part2 in the rest frame of both
72 //listed particles (12)
73
74 //angle 3 makes with 2 in rest frame of 12 (CS3)
75 double cos_phi_0 = EvtDecayAngle(_p4_p, _p4_d1+_p4_d2, _p4_d1);
76 //angle 3 makes with 1 in 12 is, of course, -cos_phi_0
77
78 switch (_spin) {
79
80 case 0 :
81 ampl=(_ampl*EvtComplex(cos(_theta*pi180inv),sin(_theta*pi180inv))*
82 sqrt(_gamma/EvtConst::twoPi)*
83 (1.0/((_p4_d1+_p4_d2).mass()-_bwm-EvtComplex(0.0,0.5*_gamma))));
84 break;
85
86 case 1 :
87 ampl=(_ampl*EvtComplex(cos(_theta*pi180inv),sin(_theta*pi180inv))*
88 sqrt(_gamma/EvtConst::twoPi)*
89 (cos_phi_0/((_p4_d1+_p4_d2).mass()-_bwm-EvtComplex(0.0,0.5*_gamma))));
90 break;
91
92 case 2:
93 ampl=(_ampl*EvtComplex(cos(_theta*pi180inv),sin(_theta*pi180inv))*
94 sqrt(_gamma/EvtConst::twoPi)*
95 ((1.5*cos_phi_0*cos_phi_0-0.5)/((_p4_d1+_p4_d2).mass()-_bwm-EvtComplex(0.0, 0.5*_gamma))));
96 break;
97
98 case 3:
99 ampl=(_ampl*EvtComplex(cos(_theta*pi180inv),sin(_theta*pi180inv))*
100 sqrt(_gamma/EvtConst::twoPi)*
101 ((2.5*cos_phi_0*cos_phi_0*cos_phi_0-1.5*cos_phi_0)/((_p4_d1+_p4_d2).mass()-_bwm-EvtComplex(0.0, 0.5*_gamma))));
102 break;
103
104 default:
105 report(DEBUG,"EvtGen") << "EvtGen: wrong spin in EvtResonance" << endl;
106 ampl = EvtComplex(0.0);
107 break;
108
109 }
110
111 return ampl;
112}
sin
double sin(const BesAngle a)
Definition BesAngle.h:210
cos
double cos(const BesAngle a)
Definition BesAngle.h:213
EvtDecayAngle
double EvtDecayAngle(const EvtVector4R &p, const EvtVector4R &q, const EvtVector4R &d)
Definition EvtKine.cc:33
report
ostream & report(Severity severity, const char *facility)
Definition EvtReport.cc:36
DEBUG
@ DEBUG
Definition EvtReport.hh:53
EvtConst::radToDegrees
static const double radToDegrees
Definition EvtConst.hh:30
EvtConst::twoPi
static const double twoPi
Definition EvtConst.hh:29

Referenced by EvtDDalitz::decay().

◆ spin()

int EvtResonance::spin ( )
inline

Definition at line 66 of file EvtResonance.hh.

66{ return _spin; }

◆ theta()

double EvtResonance::theta ( )
inline

Definition at line 57 of file EvtResonance.hh.

57{ return _theta; }
The documentation for this class was generated from the following files: